Cracked carboys after cold crashing - Help!!

[FrostyGrog]

Hi everyone first time posting here I appreciate all the advice on these forums. I need some help solving my small problem when cold crashing?

I'm fairly new to brewing but have successfully made a dozen or so batches, currently I cold crash in primary in plastic carboys and generally crash three or so 5 gallon batches at a time, I crash fast to around 34 degrees for around three days, I ferment in a chest freezer with a dual stage temp controller. Some of the brews are IPA’s with loose pellet hops so the idea is obviously to settle and clear as much as possible for easy syphoning. I simply cover the bung with sanitized foil and expect a small amount of suck back but don’t feel it has any adverse effects with O2 uptake.

So my problem is I am regularly cracking my carboys, they often crack around the base but I have also had damage on the sides, I wonder if it’s because the bottom of the carboy is sitting on the base of the fridge effectively almost freezing the sediment. Or I wonder if I gradually cold crashed the slow temp drop would be easier on my fermenters but then fear that the sediment won’t drop out as well.

Anyway I’d appreciate any advice, it's becoming a costly issue and I wonder if anybody else has ran into similar problems - Cheers in advance everyone.

 

[Newsman]

I don't know for sure, but I"m guessing it's thermal shock as the carboys are resting directly on the bottom. Try putting something under them so they don't rest directly on the bottom of the freezer. Maybe a couple pieces of 1x6 or something.

 

[FrostyGrog]

Thanks Newsman yeah that seems like the first thing I'll try, it's strange because I never notice the cracks in the sides until I wash out my carboys and notice all the cleaner run out the bottom, the mystery is how am I racking all that beer without it leaking out during syphoning? I just assumed that all the sediment was forming a cake which seals the base of the fermenter, thermal shock is probably what it is cheers.

 

[WhoDatDad78]

Frostygrog, what type of carboys are they? I've used all plastic, and never had a problem, but in the event that I make the jump to glass I want to avoid whatever you're using, lol. My vote is also thermal shock. I'd lay some closed cell foam board on the bottom and then set the carboys on top.

 

[IslandLizard]

That is a very strange phenomenon!
If it were glass I'd say thermal stress is surely a factor. But thin plastic? PET, the plastic those carboys are made of, is a rather tough material, not brittle.

Are those carboys a specific brand? Perhaps of inferior manufacture, as so many products are these days?

 

[flars]

Try cold crashing more slowly besides resting the fermentor on a pad. A slow cold crash will have the same results as a fast cold crash. It is the temperature that encourages sediment and excess yeast to drop out rather than the speed of the chilling. Might add an extra day of cold to achieve the same results.

It is also possible the cracking occurs when the carboy flexes during the lift from the chest freezer.

 

[Brewsncrabs]

I am assuming you are using plastic carboy. How long are you letting the cleaner in the carboy? PBW should not be left in carboy for days as it will deteriorate the plastic. This will lead to cracking. I had this issue and spoke to manufacturer about it. Cold crash should not be an issue.

 

[FrostyGrog]

Thanks for all the replies perfect timing as I just cold crashed two more batches this morning and some of these responses are great clues as to whats going on.

WhoDatDad. yeah the carboys are plastic but I don’t think they are PET which is now concerning me, I looked closely at them today and a third carboy that was sitting with cleaner in them has now developed a few cracks so Brewsncrabs may be onto something as well, three down two to go right now. I use Oxy Clean to clean my carboys and bottles.

The two I marked for crashing today I decided to place them high on hardwood 2 x 4’s and with the suggestion Flars made I took the temps down to 50 then to 45, 40 and I’m not going lower than 38 degrees.

I use a standard 5 gallon bottle blue (in color) plastic carboy that was previously a water carboy used for dispensing water say in offices and the such, although I forgot to mention that I live in Costa Rica which may mean that these bottles are made from a different or inferior material, the brand is Crystal a major bottling company here, these bottles are sold at the local Home Brew store for fermenting (and the water of course).

My thought has been a combination of all the comments, I think the plastic is inferior (seems solid though) and the sediment has been more or less freezing on the bottom of the fridge, this effectively swells out the base of the fermenter. Moving it, racking and then filling it with cleaner then standing it overnight weakens the walls more so hence the cracks occur.

I guess it’s off for a four hour drive to the only HBS to find a bunch of glass or PET carboys. Cheers all.

 

[IslandLizard]

^ Well, that explains a lot!

That's also why putting your location in the user's profile is so important. It would tip us off you're not just down the street from us, so to speak. Different country different products. The stuff you're dealing with never makes it onto our shelves. People have used plastic water jugs, but that type of plastic (#7) used in the U.S. is not really suitable for beer. But I've never heard about them splitting though, in the cold.

Although glass carboys may look like a valid option, their origin and quality is hard to determine. Most are made in China and the quality is sheer crap. A 5 gallon glass bottle breaking is also way more dangerous than a split plastic one.

I'd stay away from those carboys. How about using plastic buckets? The white, food grade quality, HDPE, #2. It should be stamped on the bottom.

 

[passedpawn]

pictures pleaze

 

[FrostyGrog]

Ok consider me schooled lol I guess thats why I posted this in the beginners forum, thanks for the tips I’ve learned something that I haven’t read too much about in all my searches. Despite having friends use these carboys I have used the brew buckets as well but never do they give me a good seal around the lid, they also take up more space and not being transparent they lack any indication of the state of whats going on with the fermentation.

I will look to change my profile information pronto, although I didn’t see where to put a location specifically.. hmm

As a beginner I feel home brewing should be accessible to all but in a near third world country like Costa Rica it’s close to impossible to acquire all the gear without a lot of expense and it's pretty frustrating at times, to import 4 plastic big mouth bubbler carboys it would cost me $345 plus tax so alternatives when starting out is key.

Tomorrow I will post pictures of these carboys for reference, still getting good results though thanks mostly to the info in these forums.

 

[bkboiler]

i would put money on certain parts of the fridge are getting well below freezing and the ice expansion is what's cracking the carboys. thermal shock in glass is only really gonna crack it if you pour boiling liquid into a room temp carboy or stick it in liquid nitrogen. a 2 hour ramp down to 34F would not be enough to crack even untempered glass.